How to make particles fall like snow
There are several things you could try, here are a few:

Try increasing the Drag force in Particle Settings &gt; Physics &gt; Forces to make particles affected by air resistance:


Decrease the influence of the scene Gravity in Particle settings &gt; Field Weights to make particles fall more slowly:


Add a Turbulence force field (ShiftA&gt; Force Field &gt; Turbulence) to make particles drift in random directions, simulating eddies and air currents:



Result: